The purpose of this study is to determine the optimal level of crude fiber in the diet of feral Asian monkeys, Macaca mulatta, during the quarantine period. The results, thus far, indicate that the standard 3 percent crude fiber level in commercially available laboratory nonhuman primate diets is not the optimal level. It appears that a higher level of crude fiber in the diet of feral monkeys, Macaca mulatta, reduces the number of treatment days for enteric disorders, improves stool characteristics, and does not adversely affect weight gain during the quarantine period.